Raspberry Pi inspired autopilot
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Raspberry Pi inspired autopilot
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Re: Raspberry Pi inspired autopilot
#2Looks very nice. Is Linux actually real-time enough to run autopilot code?
Re: Raspberry Pi inspired autopilot
#3Looks very nice. Is Linux actually real-time enough to run autopilot code?
Typically, APM/MavLink runs on a Arduino (my Quanum CX-20 quad runs an Mega 2650). This looks like this is a Raspberry Pi shield that I suspect contains an ATmega - so it's not Linux that is doing the flight controlling.
Re: Raspberry Pi inspired autopilot
#4Looks very nice. Is Linux actually real-time enough to run autopilot code?
Possibly not. It seems that this runs APM, which is an open source autopilot system. On their install pages, the Raspberry Pi is listed as a companion computer (presumably to be hooked to some other device that runs the code) (which this system might not do) but the Beaglebone Black (which I guess is similar to the Raspberry Pi, so might be what they do here) requires installation of realtime patches for Linux.
This works by patching the Linux kernel to make almost all of it preemptable, (replacing spinlocks with mutexes) so interrupts can be acted on more quickly.
Re: Raspberry Pi inspired autopilot
#5Looks very nice. Is Linux actually real-time enough to run autopilot code?
Typically, APM/MavLink runs on a Arduino (my Quanum CX-20 quad runs an Mega 2650). This looks like this is a Raspberry Pi shield that I suspect contains an ATmega - so it's not Linux that is doing the flight controlling.
Actually we run APM code ported to Linux, there is no Atmega on the board. There was a lot done to make this possible including special real-time Raspbian. It flies very stable and with great timing performance.
Re: Raspberry Pi inspired autopilot
#6Looks very nice. Is Linux actually real-time enough to run autopilot code?
It's fast enough in almost all cases to work. "Realtime" is more about proving worst-case bounds on all control loops.
Re: Raspberry Pi inspired autopilot
#7Using the RPi as a video encoder may be the "killer app" for this. Currently, there isn't a "ready to fly" solution that will encode video and send it out over LTE.
Re: Raspberry Pi inspired autopilot
#8Earlier quoted context omitted.
Typically, APM/MavLink runs on a Arduino (my Quanum CX-20 quad runs an Mega 2650). This looks like this is a Raspberry Pi shield that I suspect contains an ATmega - so it's not Linux that is doing the flight controlling.
Actually we run APM code ported to Linux, there is no Atmega on the board. There was a lot done to make this possible including special real-time Raspbian. It flies very stable and with great timing performance.
Very interesting, thanks!
Re: Raspberry Pi inspired autopilot
#9Looks very nice. Is Linux actually real-time enough to run autopilot code?
Possibly not. It seems that this runs APM, which is an open source autopilot system. On their install pages, the Raspberry Pi is listed as a companion computer (presumably to be hooked to some other device that runs the code) (which this system might not do) but the Beaglebone Black (which I guess is similar to the Raspberry Pi, so might be what they do here) requires installation of realtime patches for Linux. This…
We run APM on Linux. The port to Raspberry Pi is our effort and it is now supported in APM upstream.
Re: Raspberry Pi inspired autopilot
#10Looks very nice. Is Linux actually real-time enough to run autopilot code?
They are using a realtime patch on Raspbian. [1]
They also say "autopilot’s code works directly on Raspberry Pi using the APM’s Linux HAL". [2]
[1]: http://www.emlid.com/raspberry-pi-real-time-kernel/ [2]: http://www.emlid.com/navio-apm/